About Biorhythms...

The theory of biorhythms claims that one's life is affected by rhythmic biological cycles, and seeks to make predictions regarding these cycles and the personal ease of carrying out tasks related to the cycles. These inherent rhythms are said to control or initiate various biological processes and are classically composed of three cyclic rhythms that are said to govern human behaviour and demonstrate innate periodicity in natural physiological change: the physical, the emotional, and the intellectual (or mental) cycles. Others claim there are additional rhythms, some of which may be combinations of the three primary cycles. Some proponents think that biorhythms may be potentially related to bioelectricity and its interactions in the body.

In theory, then, it's a way to "chart your natural ups and downs".

Traditionally the Primary Biorhythms are these three:

Physical: A cycle of 23 days.

Emotional: A cycle of 28 days.

Intellectual: A cycle of 33 days.

Discovered later, these additional cycles are considered "Secondary Biorhythms" by some, "Extra Biorhythms" by others. They correspond to cycles mentioned in connection with the I-Ching:

Intuition or Compassion: A cycle of 38 days; possibly a Primary Biorhythm.

Esthetic: A cycle of 43 days.

Self-Awareness: A cycle of 48 days.

Spiritual: A cycle of 53 days.

Some include as "Secondary Biorhythms" cycles said to result from the interaction of the primary Biorhythms, perhaps as dissonances or overtone harmonics. Interaction of Physical and Intellectual produces a Mastery cycle. Interaction of Physical and Emotional produces a Passion cycle. Interaction of Intellectual and Emotional produces a Wisdom cycle.

If we consider the Intuition cycle as a Primary one, still more "harmonics" emerge. Interaction of Physical and Intuitive produces a Perception cycle. Interaction of Emotional and Intuitive produces a Psychic cycle. Interaction of Intellectual and Intuitive produces a Success cycle.

As one might expect, when the chart line for a given cycle is in the upper part of the graph it represents an active or "on" state. When the chart line is in the lower part of the graph, it represents the rest-and-recovery or "off" state.

"Critical days" are the days on which the chart line crosses the midline, moving from the active phase to the recovery phase or from recovery to active.

All Biorhythm cycles begin at birth, which means that on the day of birth, all the cycles are at the crossover point and about to go up, making the day of birth a "critical day" in Biorhythm terms. The three traditional Primary cycles reach this state again at approximate age 58 years, 67 days. If the Intuitive cycle is included as a Primary one, then all four Primary cycles again cross the midline together at age 77.

Biorhythms researcher and writer, Zerrin Hodgkins, who operates BioMatch.com, believes the 28-day cycle does exist but had been misidentified. Hodgkins writes that, instead, there is a 21-day Mood cycle, and that the 28-day cycle is better named as "the Reflexive cycle."

Historically, credit for discovery (or, depending on who you ask, for "inventing") of biorhythms is given to early independent researchers Fleiss, Swoboda, and Telscher.

Dr. Wilhelm Fleiss was a nose and throat specialist in the 1890's. He spotted patterns in the data of recurrent fevers and other illnesses, and of deaths, among his patients, and saw that there might be 23-day and 28-day cycles involved.

Dr. Hermann Swoboda was a professor of psychology in Vienna. He, too, was looking at patterns of fevers in his patients, and investigated the data further with an eye toward possible effects on mood and health. He also concluded that 23-day and 28-day cycles appeared to exist.

Alfred Telscher was a professor of engineering, in Austria. He observed that there was a 33-day cycle in the highs and lows of the educational performance of his students.

Internet writers are divided on the question of whether Biorhythms are a bona fide phenomenon or not. Many sites say Biorhythms "have been scientifically validated." Many other sites say Biorhythms "have not been scientifically validated at all."

The very first issue of PPC Journal in 1978 included an article, "Biorhythms?", questioning the underlying theory of Biorhythms Calculators that were then being offered in the marketplace.

On the other hand, there's this, posted on the web site of Per Bang in Denmark (where he has installed a Biorhythm Calculator of his own):

UPDATE: After having put this tool on this page many of my friend have tried it out. Several of them have afterward told me (even the ones who do not believe in 'crap like this') they can relate the fluctuations on the curves to how they have felt at the time.